1. Field of the Invention
The present invention relates to a fluorescence-enhanced chip that enhances the intensity of fluorescence.
2. Description of the Prior Art
Techniques for measuring the intensity of fluorescence emitted from fluorescent materials are important in the field of immunology and nucleic acid detection. In the case of detecting protein or nucleic acids or the like (hereinafter simply called xe2x80x98nucleic acidxe2x80x99), a nucleic acid of interest is labeled with a fluorescent material in advance, then this nucleic acid to be detected is identified by its fluorescence emission generated by the irradiation of excitation light.
In this case, the intensity of fluorescence is an index for quantifying the nucleic acid of interest. Accordingly, if the same quantities of fluorescent materials are used, the more intense the detected fluorescence intensity, the higher the detection sensitivity in that system. That is, extremely smaller quantities of protein or nucleic acid can be quantified.
For this purpose, enhancing fluorescence from fluorescent materials of equal quantity is extremely significant in immunology and the detection of nucleic acid.
U.S. Pat. No. 4,649,280 mentions a fluorescence-enhanced chip, in which the intensity of fluorescence generated from fluorescent material 4 can be enhanced as a construction having a stack of metal 2, dielectric 3, and fluorescent material 4 films on glass substrate 1 as shown in FIG. 1.
It is disclosed that the intensity of fluorescence in this case is related to the thickness d of dielectric film 3, and lithium fluoride (LiF) is used as dielectric film 3.
However, in such conventional fluorescence-enhanced chips, there are the problems that the dielectric LiF used is expensive, cannot easily be used for general purposes, and is vulnerable to corrosion.
The objective of the present invention is to solve the above problems and to realize a fluorescence-enhanced chip that is cheap, can easily be used for general purposes, and also has excellent corrosion resistance. This can be done by employing silicon dioxide (SiO2), that is cheap, can easily be used for general purposes, and also has excellent corrosion resistance, as the above dielectric.
In order to achieve such a purpose, the present invention provides a fluorescence-enhanced chip that is composed of a glass substrate and stacked films of metal, dielectric, and fluorescent material and can enhance the intensity of fluorescence generated from light-excited fluorescent material;
employs SiO2 having the film thickness of 330 nm or less as the above dielectric; and
uses silver (Ag) or aluminum (Al) as the above metal.
According to such configuration, a fluorescence-enhanced chip that is cheap and excellent in corrosion resistance can easily be realized because SiO2, which is cheap, can easily be used for general purposes, and has excellent corrosion resistance, is used as the dielectric.